Transfer data to a specific volume

I have just purchased a My Cloud EX2 Ultra 8TB. As I do not wish to duplicate the data on the device, I have set the device up in JBOD mode. Spanning is Off. It appears nonetheless that the two drives or volumes are seamless.
Is it possible to transfer data (a specific folder structure) to one specific drive of the two drive unit, and if so how?
The reason I wish to do this is I have two sets of data to backup: one set accessed frequently (daily) and one set accessed infrequently (monthly). Each set assigned to a different drive. I expect the drive used frequently will fail before the drive used infrequently.

This unit is a 2 disk NAS and its designed for redundancy to protect files

If you want more storage then get a Synology 8 disk NAS which spans redundancy across all the disks

Thanks for your reply, but it doesn’t answer my question. I’m no expert, but I’ll try and rephrase the question.
It seems in JBOD mode, without Spanning, the EX2 appears in File Explorer as one drive. I understand partitioning is not possible. Is it possible to have each of the two disks appearing separately in File Explorer? Is it possible to assign an individual Share to one of the two volumes or disks.

EX2 is not that sophisticated

the more advanced models are much safer choice with fault tolerance and better performance